The present invention relates to an improvement in the type of temporary surface covering particularly for movement of vehicles on sandy, muddy or marshy ground, which is the object of French patent No. 2 718 158 in the name of the applicant.
The above patent discloses a covering characterized in that it is constituted by a woven structure formed from weft threads of the monofilament type disposed in a single layer and warp threads also disposed in a single layer, the weave of the woven structure being such that each warp thread intertwines with the following weft threads, preferably and very proximately, half of the intersections of the rows and columns of the weave, the warp thread being left in the remaining intersections, such that for each warp thread, there is obtained at least one single and tight weave region followed by a float region, the alternation of the above different zones giving rise to retightening the weft threads creating a substantial relief of the fabric thus produced.
For certain applications, it appears to be useful or necessary to improve the load-bearing capacity of this covering so as particularly to reduce the phenomenon of rutting that can result from the conjunction, on the one hand, of the inconsistent nature of the ground, and, on the other hand, of the weight of the vehicle and its mode of movement over the ground.
From EPO 617 160 there is known a composite covering structure constituted by a woven structure clad on its two surfaces with an elastomeric layer.
From place to place in this composite structure are provided pockets adapted to receive flexible or rigid elements, or to be inflated with the help of a fluid under pressure.
To this end, certain of the warp and weft threads of the woven structure are separated from the other threads so as locally to divide the original woven structure.
Such a covering structure is necessarily made fragile in line with the pockets and its physical properties are very substantially modified and altered because of the loss of integrity of the woven structure adjacent the pockets.
The present invention has precisely for its object to overcome the drawbacks of the above coverings.
To this end, the invention has for its object a temporary surface covering, particularly for the movement of vehicles over sandy, muddy or marshy ground, of the type with a woven structure formed of warp and weft threads whose weave is such that each warp thread intersects or intertwines with following weft threads, preferably and very proximately, half the intersections of the rows and columns of the weave, the warp thread being left at the remaining intersections, such that, for each warp thread, there is obtained at least one region of simple and tightened weave followed by a region of floats, characterized in that a second auxiliary woven structure is superposed and comprises a layer of warp threads and a layer of weft threads, the connection between the two woven structures being effected in the course of a same weaving operation simultaneously with the overlapping of the structures, so as to constitute between the two structures, from place to place, tubular pockets oriented according to the warp threads or according to the weft threads, said pockets serving for the reception of elements provided for various purposes.
According to an application of the invention to the reinforcement of the rigidity of the covering, the pockets thus constituted receive at least one elongated rigidification element, for example a bar of composite material of several tens of millimeters in diameter.
Such bars, and particularly when they are inserted in the pockets constituted transversely to the covering, which is to say parallel to the weft threads, substantially improve the load-bearing capability whilst reinforcing the gripping of the contacting surface in particular with the tires of vehicles moving on such a covering.
When the pockets are provided in the direction of the warp threads, along the longitudinal axis of the covering, the elements constituted for example by flexible tubes inflated by a fluid under pressure, permit conferring on the assembly of the covering a substantial rigidity and a high stability.
Other applications of the device of the invention can be envisaged, for example the detection in or on the ground on which the covering is deployed, or dangers such as mines or hidden pits, in which case the pockets constituted in the covering can receive any detection means or device and/or device for the destruction of mines.